Name of lambda parameters

[Remi Forax]

(CC Alex Buckley)

As noticed recently on lambda-dev mailing list,
there is no way to get the parameter names of a lambda because
there is no way to do reflection on a lambda (an object implementing a 
functional interface) to get the corresponding declared method.

do we need a static method Parameter[] Method.getLambdaParameters(Object 
lambdaProxy) ?
The fact that it takes an object and not stable value (like a class, 
etc) doesn't seem a good idea

This may require bookkeeping when doing the functional interface conversion.
By example, the generated lambda proxy can implement a non-public 
interface to extract this information and for the method handle proxy, 
it can use the internal API used by the metafactory to crack the method 
handle.

So, like serialization, may we need to have a special empty interface 
NamedParameterLambda to tag these specific lambdas ? In that case, the 
method getLambdaParameters can be a static method of NamedParameterLambda,
Parameter[] getLambdaParameters(NamedParameterLambda lambdaProxy).

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